题目：On spin-Hall magnetoresistance

报告人：王向荣 教授，香港科技大学物理学系

时间：2023年4月6日（周四）上午10：00-11：00

地点：知新楼C702 量子报告厅

邀请人：解士杰 教授、秦伟教授

摘要：

The observation of magnetoresistance (MR) varying with the rotation of magnetization in the plane perpendicular to the electric current is an important discovery in spintronics in recent years. The famous conventional anisotropic MR (AMR) says that the resistance of a polycrystalline magnetic material must depend on magnetization component along the current direction only, thus cannot account for this newly observed unusual AMR (UAMR). This UAMR leads to the notion of the spin-Hall MR (SMR) in the famous SMR theory. However, the SMR theory may only explain UAMR observed in heavy-metal/magnetic-insulator bilayers, not other types of bilayers. Here, we present a two-vector theory that can explain not only all existing experiments on the unusual angular dependence of longitudinal and transverse resistivity when the magnetization rotates in three mutually perpendicular planes, but also how three amplitudes of MR angular oscillation are related to each other. The theory is very general and its correctness depends only on the assumption that the magnetization and interfacial field are the only vectors affecting electron transport. Experiments that can test this theory against the SMR theory are also proposed.

报告人简介：

  王向荣教授目前就职于香港科技大学，是中国引进的“海外高层次人才”，山东省“万人计划”第一层次人才入选者。于1984年通过CUSPEA（中美联合研究生入学）考试，从武汉大学赴美国，于1986年、1990年分别获得美国Rochester大学的硕士学位和博士学位。1990年在美国明尼苏达大学做助理研究员，1992年进入香港科技大学工作。历任3、4、5届理论与计算物理国际研讨会和第3届固体量子计算国际研讨会的组织委员会委员；国际磁学会议、国际材料研究大会的分会主席；为多个国际权威学术期刊如PRL、APL、EPL等的审稿人。

  主要从事凝聚态理论物理方面的研究，并已在变程跳跃导电中的负磁阻、超晶格电子输运、二维电子气和石墨烯中的KT转变、场致和电流导致的磁性翻转、skirmion微观机制等方面做出不少开拓和创新的研究成果。目前已Nature Materials、Physical Review Letters、Advanced Functional Materials、Nano Letters、Physical Review B、Applied Physics Letters等国际著名期刊上发表二百多篇高水平论文，多次受邀参加国际学术会议并作邀请报告。